What I think has happened here is that Jet2 are to start services but the announcement wasn't due to be made this soon and people are just speculating as to why it didn't happen. As someone else said, most of jet2's bases are announced in Aug/Sept so (hopefully) I would think that they will announce something then.
Plus 737-800's - 6-18 months??? Thats a big gap do you mean 6-8 months?